In deep trolling for various kinds of fish it has long been known to support the required sinker, not on the fishing line itself, but rather on a separate downrigger line wound on a separately controlled downrigger reel. Conventionally, the fishing line is releasably secured to the sinker during trolling but springs free therefrom when struck by a fish. This permits the fish to be played and boated without encumbrance by the weight of the sinker, yet retains the sinker on the downrigger line for further use.
Entirely manually operated downriggers have long been widely commercially available and typically comprise a boat-supported frame rotatably mounting a hand-cranked line-carrying reel. The reel may be sized so that one rotation thereof corresponds to winding of a convenient length of line, for example two feet. The fisherman typically keeps track of the amount of line unwound from the reel by himself counting reel revolutions or by watching the dial of a conventional small mechanical counter tripped once or twice per revolution by the adjacent reel.
It has also been known to connect an electric motor to the reel for winding and unwinding the downrigger line, as disclosed for example in U.S. Pat. Nos. 3,719,331; 3,910,524 and 3,916,555. However, such prior devices fail to provide for automatic stopping of motor driven unwinding, requiring the fisherman to direct his attention continuously to the unwinding operation, as by counting reel rotations or watching a mechanical counter for the desired number of reel rotations and then manually switching off the motor. This wastes fisherman's time that might better be spent on other matters such as handling of other fishing gear or boat handling.
Several, for example four, downriggers are frequently used on a single boat to weight a similar number of fishing lines. When a fish is hooked on one fishing line, there may be a considerable risk of tangling of lines unless the remianing fishing lines and all downrigger lines are reeled in. Particularly in this situation, automatic shut off for reeling in is desirable to rapidly and without much attention from the fisherman avoid line tangling. On the other hand, considerable fisherman time is wasted if all of the several downrigger lines must be manually stopped in being relowered to the fishing depth. The time loss if either winding up or unwinding of downrigger lines is not automatic and it is particularly disadvantageous where, as is often the case, fish are striking in rapid succession but only over a relatively short time span such that any delay in raising and lowering downrigger lines may mean lost fish.
Prior U.S. Pat. No. 3,922,808 does provide automatic lowering, but not of a preselected length of line. Rather, lowering in this patent is to a preselected level above the lake or sea bottom or to a desired water temperature level. Unfortunately either of these capabilities requires complex and costly electronic circuitry for sensing bottom depth or water temperture, for determining the location of the downrigger weight with respect thereto, and for electronically controlling motor actuation. The result may thus as a practical matter be an initial cost beyond the budget of many fishermen, susceptibility to erratic operation due to static or engine ignition or atmospheric interference, relative fragility and susceptibility to damage from wind driven spray and waves, a need for sophisticated electronic knowledge and instrumentation for repair, and downrigger positioning capability outside the need of many fishermen. Also, the prior device is intended to continuously and automatically raise and lower the downrigger weight as the depth of the bottom or water temperature vary as the boat trolls from place to place, thereby accelerating reel drive wear and battery drain.
In addition, the apparatus of such prior U.S. Pat. No. 3,922,808, in its depth mode, depends on the echo of a sonic signal from the lake bottom and could be activated while passing over schools of fish, sunken vessels, or other submerged objects, leading to erroneous reel activation. Also in its depth mode, the patented apparatus is not a "stand alone" unit, since an expensive digital depth sounder must be used with it, the patented apparatus not being an automatic depth downrigger as such, but only an accessory which makes a digital depth sounder or control for a downrigger which does not have a calibrated depth control. Also, fishermen are now to a large extent using recording-type depth sounders which visually indicate on graph paper the depth at which fish are located, enabling the fisherman to drop has downrigger, with attached fishline, to that depth. However, such recording-type depth sounder, insofar as I am aware, does not have the necessary BCD output required by the patented downrigger device. This would necessitate having two depth sounders on the same boat, namely a recording type and a digital type. Aside from the obvious added cost, their close proximity raises a strong possibility of the two sounders interfering with each other.
Further, the aforementioned patents either fail to provide automatic stopping of both winding and unwinding reel rotation, or do so by separate and unrelated portions of the apparatus, thereby further increasing apparatus complexity and cost.
Accordingly, the objects of this invention include provision of a downrigger apparatus for fishing, which is capable of electric motor driven unwinding and winding of downrigger line and automatic stopping when a preselectable length of line has been unwound from the reel and also when a previously unwound length of line has been substantially fully rewound, so as to free the fisherman for other activity during such unwinding and winding operations.
A further object is to provide an apparatus, as aforesaid, adjustable to preselect the length of downrigger line to be unwound, manually actuable to initiate such unwinding of line from the reel which will automatically stop unwinding at the preselected length, and which will hold at that length until further manual intervention occurs.
A further object is to provide an apparatus, as aforesaid, which is free of complicated and expensive electronic circuitry, which is relatively inexpensive and simple to produce, which is primarily mechanical in nature and capable of maintenance and repair by persons with little training.
Further objects and purposes of this invention will be apparent to persons acquainted with apparatus of this general type upon reading the following specification and inspecting and accompanying drawings.